Orthodynamic Roundup

[Vidmaven]

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WOW! That's an impressive collection of HP-50s.

 

[kalbee]

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Good to have spare parts (drivers tend to fail) and be ready to mod the ultimate HP50.
 
 

:S Hope that never happens to me...
I don't have spare parts for my orthos.
And I left a bunch of them home. Hopefully they're okay >_< it's been 3 months they've been sitting in a box unattended...
 
and wow that's... an incredible amount of HP-50s lol.

 

[MDR30]

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:S Hope that never happens to me...
I don't have spare parts for my orthos.
And I left a bunch of them home. Hopefully they're okay >_< it's been 3 months they've been sitting in a box unattended...
 
and wow that's... an incredible amount of HP-50s lol.

 
Well, the construction with the central rivet probably caused some problems in the automated production process.
 

 
The diaphragm is sensitive and if hole and pin are not properly centered the diaphragm will bulge with a risk of broken coil trail.
 

 
Either the driver is dead or signal comes and goes depending on membrane movement. dBel 84 is the expert on this and he has fixed quite few with a silver pen or silver epoxy, I believe. This requires skill and surgical precision. Easier to get a spare driver.
 
In my experience about 2-3 of 10 headphones with the 46 mm driver (HP50, HP3, HP2 etc) have this problem. The 55 mm HP1 driver seems to be less afflicted.
 
Also note that the original HP50 produced for the Yamaha Electone electric organ (sometimes with an A suffix, or "For Electone") has a less tight membrane for reproducing the low pedal notes of the organ (see text on box below).
 

 
These models are recognized by their mono plug.
 

 
 

 
Yamaha B20-RC Electone electric organ with bass pedals. Headphone jack is under the keyboard to the right (red ring), hence the unusual right side single cable entry of the HP50.
 

 

 

[audiofreakie]

Unmoded T50RP V2.
just recable and direct from ipod classic.

 

 

[kalbee]

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In my experience about 2-3 of 10 headphones with the 46 mm driver (HP50, HP3, HP2 etc) have this problem. The 55 mm HP1 driver seems to be less afflicted.
 
Also note that the original HP50 produced for the Yamaha Electone electric organ (sometimes with an A suffix, or "For Electone") has a less tight membrane for reproducing the low pedal notes of the organ (see text on box below).

Do you know if these less tight membranes are part of the cause of the rivets not holding the membrane well?

 

[MDR30]

Do you know if these less tight membranes are part of the cause of the rivets not holding the membrane well?

I don't understand. Please rephrase the question and define the problem.

 

[kalbee]

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I don't understand. Please rephrase the question and define the problem.

Sure, I'll just highlight the spots from your original post.
 
Quote:

 
Well, the construction with the central rivet probably caused some problems in the automated production process.
 

 
The diaphragm is sensitive and if hole and pin are not properly centered the diaphragm will bulge with a risk of broken coil trail.
 
In my experience about 2-3 of 10 headphones with the 46 mm driver (HP50, HP3, HP2 etc) have this problem. The 55 mm HP1 driver seems to be less afflicted.
 
Also note that the original HP50 produced for the Yamaha Electone electric organ (sometimes with an A suffix, or "For Electone") has a less tight membrane for reproducing the low pedal notes of the organ (see text on box below).

Thus I was wondering if the less tight membranes of the original HP50's are more prone to diaphragm bulging ---> risk of broken coil trail.

 

[stratocaster]

I have been working on my woodie orthos a bit and I have developed three different ways of closing the cups in a way that allows both easy and quick opening/closing and secondly variable venting. 
 
My Ebony HP-1s have been equipped with 2 aluminum venting layers that can change the amount of venting by turning the top disc against the bottom disk that has a variety of holes of different sizes cut out. That way you can quickly modify the airflow without opening the cups. 
 

 
For my NAD RP-18  I am using a wood disc with a ring of felt  as well as a center hole for venting. This basically runs down to a (semi) closed setup. Works fine with the NADs (using HM5 pads and tense damping).
 

 
When I want to go for an open setup , I am using a ring of (ebony) wood holding a metal mesh. Again this ring/disc can be easily removed and put in place to make the process of modding easier and quicker.
 

 

[kalbee]

Dang... nice work as usual.

And seems someone finally made the spinning port size/number changer. Would be interesting to know if the location of the holes affect the sound.

 

[stratocaster]

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And seems someone finally made the spinning port size/number changer. Would be interesting to know if the location of the holes affect the sound.

 
To tell you the truth, as far as I am concerned the damping behind the driver is the far more important aspect. Once you get that right you do not really need any fancy venting hole spinner kind of thing. But it was fun developing the thing. Dunno, but maybe it will prove to be helpful one day.

 

[Armaegis]

I did a T50rp transplant into a Beyer COP and the effect of the bass vents is not nearly as drastic as with the original drivers. 

 

[MDR30]

Sure, I'll just highlight the spots from your original post.

Thus I was wondering if the less tight membranes of the original HP50's are more prone to diaphragm bulging ---> risk of broken coil trail.

Sure, I'll just highlight the spots from your original post.

Thus I was wondering if the less tight membranes of the original HP50's are more prone to diaphragm bulging ---> risk of broken coil trail.

I would think so, even though Wualta, Ludoo and dBel84 have more experience in this area. The problem is inherent in the ortho principle, and even modern designs have shown they're not foolproof (Audeze, Hi-Fi Man). Aluminum is brittle, gold more flexible (albeit heavier, more moving mass).

The standard HP50 without headband pad and with dual entry cable, as well as the HP3, usually have a tighter membrane which likely was easier to assemble with precision (rivet stampers). In my ears they also sound better. But there are no absolutes concerning types and production runs of these Yamahas, as you can see if you look at HP3 on Wikiphonia.

On the other hand, it seems vintage and present day Fostex headphones are much more reliable. But they were also ortho pioneers, together with Wharfedale and PMB.

 

[dBel84]

I have never seen a broken coil in a yamaha - they would have to flex at strange angles to put much stress on the coil. The YH1000 as we know was prone to corrosion but that was a different matter. In fact yamahas seem to be far hardier than the fostex ( v1 ) of which I have seen numerous driver failures. This could be a flex concern as it seems that the center is the weak link - the traces from the 2 sides are attached at the center and all too often , this continuity fails. 
 
..dB

 

[bluemonkeyflyer]

I've been looking for a 5-pin DIN to 1/4" TRS plug for my TDS-16 (Kiev). I finally found a couple in Germany and got to hear them for the first time since I bought them last year. This set of TDS-16 has much more bass than my 3 sets of TDS-15. I think the bass is a bit loose so I cut out a circle of double-sided tape to damp the external vents.
 
The vents are approximately 5 mm in diameter and there are about 25. They appear to be covered on the inside with some sort of felt. I have not opened them because I want to try external mods, first.
 
The photo shows only one of the vents left "exposed." I think this helps to control the bass but still leaves plenty of slam. I haven't done much A/B comparisons so it could be nothing more than expectation bias. If anyone has tried modifying these 'phones, suggestions would be appreciated.
 
I will eventually get around to measuring their FR in stock form and compare to measurements with all vents sealed vs 1 vent open. 
 
So far, no luck finding a TDS-16 (Smela) that others have said sounds better.
 

Amfiton Echo TDS-16 (Kiev): 16 ohm
 
Double-sided tape ring seals vents - only one vent left open.

 

[vid]

Be warned: measurements are generally frowned upon around here. Though I welcome them.